Polyvinyl chloride moulding composition

Abstract

A notched-impact-resistant polyvinyl chloride moulding composition having a low shrinkage value, based on vinylchloride polymers and impact-resistant modifiers, containing from 0.01 to 5% by weight, based on the total of vinylchloride polymer and impact-resistant modifier, of liquid polysiloxanes having viscosities of from 20 to 100,000 cSt and/or solid polysiloxanes having molecular weights of from 20,000 to 500,000 and optionally conventional additives and auxiliaries.

We claim: 
     
       1. A notched-impact-resistant moulding composition having a low shrinkage value selected from the group consisting of I. a mixture consisting of (a) from 99 to 85% by weight of polyvinyl chloride, (b) from 1 to 15% by weight of ethylene-vinyl acetate copolymer containing from 25 to 60% by weight of vinyl acetate and having a molecular weight of from 20,000 to 500,000 and (c) from 0.01 to 5% by weight, based on the total weight of (a) plus (b), of a polysiloxane;   II. a mixture consisting of a graft polymer of 3 to 15% by weight of ethylene-vinyl acetate copolymer containing from 25 to 60% by weight of vinyl acetate and having a molecular weight of from 20,000 to 500,000 having grafted thereon from 97 to 85% by weight of polymerized units of vinyl chloride and from 0.01 to 5% by weight, based on the weight of said graft polymer, of a polysiloxane and   III. a mixture consisting of polyvinyl chloride, a graft polymer of from 60 to 4% by weight of ethylene-vinyl acetate copolymer containing from 25 to 60% by weight of vinyl acetate and having a molecular weight of from 20,000 to 500,000 having grafted thereon from 40 to 96% by weight of polymerized units of vinyl chloride, the total content of said ethylene-vinyl acetate copolymer in said mixture being from 3 to 15% by weight, based on the weight of polyvinyl chloride and said graft polymer, and from 0.01 to 5% by weight, based on the total polyvinyl chloride and graft polymer, of a polysiloxane, said polysiloxane of each of I, II and III being selected from the group consisting of polydimethylsiloxane having methyl terminal groups and a viscosity of 20 cSt; polydimethylsiloxane having methyl terminal groups and a viscosity of 140 cSt; polymethylphenylsiloxane having methyl terminal groups and a viscosity of 350 cSt; polymethylphenylsiloxane having methyl terminal groups and a viscosity of 1,000 cSt; polydimethylsiloxane having OH terminal groups and a molecular weight MW of 90,000 and polydimethylsiloxane having vinyl terminal groups and a molecular weight MW of 500,000.     
     
     
       2. The mixture of the notched-impact-resistant moulding composition of claim 1 wherein said polysiloxane is present in an amount of from 0.1 to 2.0% by weight.